is my 50-135 too soft a 2.8

qksilver · 04-19-2008, 11:21 AM

I have been happy with my 50-135. Lately however, I have noticed it to be a little fuzzy at 2.8 and 135mm.

attached are some photos with 100% crops. let me know if your 50-135 is this soft or if it should be sharper at 135mm and 2.8

Last edited by qksilver; 05-24-2008 at 04:19 AM.

augustmoon · 04-19-2008, 06:16 PM

what was your shutter speed?
SR on or off?
Using the lens hood? (looks like strong light coming in from upper right)

Mine seem a lot sharper, trying to look for some now to post... from the zoo

I have some shots at 135 f/5.6 that seem soft like this, but it was at the beach and the bright sun was casting glare at a right angle to the lens, not sure whether that affected the optics, or messed with the AF or if just that all that glare made everything look fuzzy behind it.

I'll try to find the images at 2.8 that are sharp...

Brian

qksilver · 04-19-2008, 06:37 PM

shutter speed was 1/250 shake reduction was on
lens hood was used

jbcampbell · 04-20-2008, 08:27 AM

It's really hard to make a judgement on photos like that, the subject could have moved a bit towards the camera, etc...
If you really want to test it put it on a tripod with SR off & shoot a still subject like a sign or billboard.

daacon · 04-20-2008, 08:39 AM

Yep that is the best controlled (tripod) also what was metering ? where was the focal point ? ISO ? ........... seems soft you are right.

d.bradley · 04-20-2008, 09:13 AM

I wonder if its focus accuracy or "softness"...? I can't comment on the lens as I've not seen it in action.

Sharpness is also sometimes affected by focus distance, something largely ignored by reviewers...

qksilver · 04-20-2008, 01:15 PM

can someone post some 100% crops at 2.8 of their 50-135 so i can compare??

raz · 04-20-2008, 01:24 PM

the second crop looks way out of focus not just softness...try to post the whole images in full size to see if we spot where does it focus

qksilver · 04-20-2008, 02:10 PM

this is the largest i could get them on flickr

qksilver · 04-20-2008, 02:12 PM

**Canada_Rockies** · 04-20-2008, 10:30 PM

You have a hair thin depth of field at f/2.8, and that might be misleading you. It almost appears to me in the larger Flickr image that the focus is on the papers in the lady's left hand, a bit in front of her. If you mentally draw an X from corner to corner, the geometric center of the image, where the focus point is, is on the papers. As a check, open the original on your computer, and check the area of the papers for focus accuracy.

FotoPete · 04-20-2008, 11:29 PM

Yea I agree with Albert, the focus seems to come up a bit ahead of the person. Front focusing?

Though I'd be sure before anything as AF sensors do like to focus more on sharp edges and distinct lines.

gkopeliadis · 04-21-2008, 03:46 AM

Originally posted by qksilver

can someone post some 100% crops at 2.8 of their 50-135 so i can compare??

K10D, no SR, tripod mount, center of image, point auto focus on the center of cross, ISO 100, PEF to bmp by Photoshop SC3-camera raw at default settings.
1st crop @135mm / f2,8
2nd crop @135mm / f5,6
I find this behavior normal to fast telephoto lens. Actualy seems better than a sigma 50-150 I'm testing these days (I'll post more on the comparison after a few days).
Note that at 2,8 depth of field is very shallow @135mm so small front-back focus issues or exact point of focus become serious.

qksilver · 04-21-2008, 06:55 PM

Thanks for the 100% crops. That helps. Mine is about that soft at 2.8 as well so I am going to assume this is normal unless someone disagrees

k100d · 04-21-2008, 07:01 PM

strictly on Photozone charts, it shouldn't be that much softer in the center at least
Pentax SMC-DA* 50-135mm f/2.8 ED [IF] SDM - Review / Test Report

04-19-2008, 11:21 AM	#1
qksilver Senior Member Join Date: Oct 2007 Location: Northern Virginia Photos: Gallery Posts: 131	is my 50-135 too soft a 2.8 I have been happy with my 50-135. Lately however, I have noticed it to be a little fuzzy at 2.8 and 135mm. attached are some photos with 100% crops. let me know if your 50-135 is this soft or if it should be sharper at 135mm and 2.8 Last edited by qksilver; 05-24-2008 at 04:19 AM.

04-19-2008, 06:16 PM	#2
augustmoon Inactive Account Join Date: Mar 2008 Location: Toronto, San Diego, Seattle Posts: 455	seems a bit soft or out of focus what was your shutter speed? SR on or off? Using the lens hood? (looks like strong light coming in from upper right) Mine seem a lot sharper, trying to look for some now to post... from the zoo I have some shots at 135 f/5.6 that seem soft like this, but it was at the beach and the bright sun was casting glare at a right angle to the lens, not sure whether that affected the optics, or messed with the AF or if just that all that glare made everything look fuzzy behind it. I'll try to find the images at 2.8 that are sharp... Brian

04-21-2008, 03:46 AM	#13
gkopeliadis Veteran Member Join Date: Mar 2008 Location: ATHENS, GREECE Posts: 308	Originally posted by qksilver can someone post some 100% crops at 2.8 of their 50-135 so i can compare?? K10D, no SR, tripod mount, center of image, point auto focus on the center of cross, ISO 100, PEF to bmp by Photoshop SC3-camera raw at default settings. 1st crop @135mm / f2,8 2nd crop @135mm / f5,6 I find this behavior normal to fast telephoto lens. Actualy seems better than a sigma 50-150 I'm testing these days (I'll post more on the comparison after a few days). Note that at 2,8 depth of field is very shallow @135mm so small front-back focus issues or exact point of focus become serious. Attached Images Last edited by gkopeliadis; 04-21-2008 at 03:52 AM.

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04-19-2008, 06:37 PM	#3
qksilver Senior Member Join Date: Oct 2007 Location: Northern Virginia Photos: Gallery Posts: 131 Original Poster	shutter speed was 1/250 shake reduction was on lens hood was used

04-20-2008, 08:27 AM	#4
jbcampbell Senior Member Join Date: Aug 2007 Location: Lynchburg, VA Posts: 215	It's really hard to make a judgement on photos like that, the subject could have moved a bit towards the camera, etc... If you really want to test it put it on a tripod with SR off & shoot a still subject like a sign or billboard.

04-20-2008, 08:39 AM	#5
daacon Veteran Member Join Date: Mar 2007 Location: Alberta,Canada Photos: Gallery Posts: 20,914	Yep that is the best controlled (tripod) also what was metering ? where was the focal point ? ISO ? ........... seems soft you are right.

04-20-2008, 09:13 AM	#6
d.bradley Veteran Member Join Date: Feb 2007 Location: Ontario Photos: Gallery Posts: 631	I wonder if its focus accuracy or "softness"...? I can't comment on the lens as I've not seen it in action. Sharpness is also sometimes affected by focus distance, something largely ignored by reviewers...

04-20-2008, 01:15 PM	#7
qksilver Senior Member Join Date: Oct 2007 Location: Northern Virginia Photos: Gallery Posts: 131 Original Poster	can someone post some 100% crops at 2.8 of their 50-135 so i can compare??

04-20-2008, 01:24 PM	#8
raz Senior Member Join Date: Apr 2007 Location: Timisoara, Romania Posts: 248	the second crop looks way out of focus not just softness...try to post the whole images in full size to see if we spot where does it focus

04-20-2008, 02:10 PM	#9
qksilver Senior Member Join Date: Oct 2007 Location: Northern Virginia Photos: Gallery Posts: 131 Original Poster	this is the largest i could get them on flickr

04-20-2008, 02:12 PM	#10
qksilver Senior Member Join Date: Oct 2007 Location: Northern Virginia Photos: Gallery Posts: 131 Original Poster

04-20-2008, 10:30 PM	#11
Canada_Rockies Loyal Site Supporter Join Date: Nov 2007 Location: Sparwood, BC, Canada Photos: Gallery \| Albums Posts: 12,385	You have a hair thin depth of field at f/2.8, and that might be misleading you. It almost appears to me in the larger Flickr image that the focus is on the papers in the lady's left hand, a bit in front of her. If you mentally draw an X from corner to corner, the geometric center of the image, where the focus point is, is on the papers. As a check, open the original on your computer, and check the area of the papers for focus accuracy.

04-20-2008, 11:29 PM	#12
FotoPete Veteran Member Join Date: Feb 2007 Location: Toronto Photos: Gallery Posts: 1,774	Yea I agree with Albert, the focus seems to come up a bit ahead of the person. Front focusing? Though I'd be sure before anything as AF sensors do like to focus more on sharp edges and distinct lines.

04-21-2008, 06:55 PM	#14
qksilver Senior Member Join Date: Oct 2007 Location: Northern Virginia Photos: Gallery Posts: 131 Original Poster	Thanks for the 100% crops. That helps. Mine is about that soft at 2.8 as well so I am going to assume this is normal unless someone disagrees

04-21-2008, 07:01 PM	#15
k100d Veteran Member Join Date: Feb 2008 Location: Toronto Posts: 3,911	strictly on Photozone charts, it shouldn't be that much softer in the center at least Pentax SMC-DA* 50-135mm f/2.8 ED [IF] SDM - Review / Test Report